Step-by-step explanation:
Both of these mistakes were made bc someone didn't know what "supplementary" means. If two angles are supplementary (an angle and its supplement) they ADD UP TO 180°
Mistake: They used 90 in the original set up. These angles do not add up to 90°.
47+x=180 subtract 47 from both sides
x = 133°
In #5, MISTAKE: the original set up, they put the two angles equal to each other. The two shown angles laying next to each other add up to 180°
115°+ (5x-10)°= 180° combine like terms
5x + 105° = 180 subtract 105 from both sides
5x = 75 divide by 5
x = 15
